Concrete molding apparatus



y 29, 1951 K. P. BILLNER 2,555,022

CONCRETE MOLDING APPARATUS Original Filed Sept. 5, 1947 2 Sheets-Sheet 1 a4 54 3; F" 4o WW Pm 64 58 u 46 /Z 2 145a J' ""i5ffifi 3 64 311 4; 56 To VMUUMIPUMP 15 82: if" B g 5521012.

'z i /m y 1951 K. P. BILLNER CONCRETE MOLDING APPARATUS OriginaLFiled Sept. 5, 1947 '2 sneets-shet 2 INVENTOR- ARI. P B/LL ER ATTORNEY Patented May 29, 1 951 CONCRETE MOLDING APPARATUS 1 Karl P. Billner, Philadelphia, Pa., assignor to Vacuum Concrete, Inc., a corporation of Pennsylvania Original application September 5, 1947, Serial No. 772,324. Divided and this application February 7,1949, Serial N0. 75,039

Claims. (01. 25-131) Whereas precast concrete techniques have obviated the need for muchof the form-work required where concrete is cast in situ, current practicestill requires the site erection of forms for perfecting the joints between such precast members. Inasmuch as the material and labor required .in the construction of formsv represents anappreciable-portion of the total cost of concrete work, it will be apparent that the use of prefabricated joint forms-which are rapidly applicable to and removable from the structure and capable of repeated use, will effect tremendous savings in the building industry.

It. is accordingly an object of this invention to provide forms which can be secured to spaced structural members by means of subatmospheric pressures so as to bridge the gap betweenthem and permit the pouring of a plastic concrete composition and at the proper time, by removal of such subambient pressures, release such forms or partsthereof and transfer them to the next joint to be-formed. For many applications of the present invention, it-is preferable that the molding surface of the forms thus secured to bridge the structural members, permit the application of subatmospheric pressure-to the plastic composition; itself for the purpose of removing such excessvehicle as water, to produce a more compact; solidified. body in much shorter time than would be possible under natural atmospheric.

conditions.

According to the present invention, in forming a joint between spaced structural members,'such members are bridged with a closure which is secured to at least one. of them by the application of subatmospheric pressurefand a plastic composition deposited between the members and the closure. As already indicated'the composition may be subjected to subatmospheric pressure as well. It is also contemplated that opposed closures be thus employed .to bridge the structural members and that such closures be secured to at least one of the structural members. The application of subatmospheric pressure to the composition may be produced through the closure or closures, by providing them with a perforated or foraminous surface for contact with the composition, whichmay be accomplished by covering the open side of an otherwise closed mat with a fabric permitting the passage of a vehicle such as water while serving asyabarrier to solidparticles of ,thesizes employed in the composition.-

As previously set forth by the present inventor, a substantial portion of the water added in the production of a concrete mix for commercial use serves the sole purpose of producing workable consistencies and represents an excess insofar as the requirements for setting are concerned. It is this excess vehicle, or a substantial portion thereof which can be removed to advantage after the concrete mix has been deposited, to produce structures which become self supporting soon after deposition and which possess superior characteristics of compactness, strength, impact resistance and uniformity, as compared with concrete structures produced by more commonly known commercial methods.

The apparatus contemplated herein for casting a moldable plastic composition between spaced structural members comprises a molding surface for contact with the composition, sealing means on the surface forv engagement with a surface portion of the members, holding means connected with the molding surface comprising a mat having sealing means for engagement with an adjacent surface portion of the members, and means for applying subatmospheric pressure intermediate theholding means and the adjacent surface portion. It is also intended that means for applying subatmospheric pressure between the molding surface and the composition be provided. Aperforate molding surface of the type hereinabove mentioned. and described elsewhere among applicants patents and applications, may assume the form of a fabric covering for the open side of an otherwise closed mat,-supported with respect to the mat by spacing means such as 'Wire mesh or other suitable material.

The holding means maycomprise a plurality of mats to be secured to the structural members adjacent themolding surface. Marginal sealing means on the molding surface may engage adjacentsurfaces of the structural members and provide a seal between the molding surface and .the holding means as well as between the composition and atmosphere. The holding means maybe integral with or separable from the molding surface and the holding means may provide portions overhanging the molding surface to serve as a bearing for properly fixing the molding surface during the molding operation.

It has been found in actual practice with the apparatus of the present invention, that shortly after subatmospheric pressure has been applied to the composition, the separable holding means can be removed, since the composition will become self supporting so rapidly after a portion of the'excess vehicle has been removed that the static forces tending to displace the molding surface are rapidly and appreciably reduced. And

as a matter of fact, the time required for retain- ,ing the molding surface itself in position is diminished to a relatively short period because of the rapidity with which the composition becomes self supporting under the influence of the subatmospheric pressure to remove the excess water.

A more complete understanding of the invention will follow from a detailed description based upon the accompanying drawings wherein:

Fig. 1 is a fragmentary perspective illustrating the invention as applied to wall construction;

Fig. 2 is a fragmentary section taken along line 2-2 of Fig. 1;

Fig. 3 is an elevation of one of the forms shown at the right of Fig. 1; and Fig. 4 is a section taken along line 44 of Fig. 3.

The precast concrete wall members Ill and I2 define a corner of the structure under consideration and an adjacent structural member I4 coplanar with one of the corner forming members i2 cooperates in forming a portion of one of the walls. An external closure I6 is shown as bridging the corner forming members, retained in position by a holder [8 applied to a portion of the member 10 and a holder applied to a portion of the member I2. An internal corner closure 22 is similarly positioned to bridge the corner forming members by a holder 24 applied to a portion of the member 10 and a. holder 26 ap.- plied to a portion of the member [2. .These corner closures are depicted as separable from their respective holders while, the closures 28 employed for producing the running joint between the elements 12 and [4 have been illustrated as unitary with their holders 30, and applied to opposite surface portions of the spaced elements I2 and I4.

Each of the holders is. provided with marginal sealing means 32 to exclude atmosphere when it defines a closed chamber with the surface of the structural member to which it is applied for producing therein a subatmospheric pressure through a line 34 communicating with a suitable source of such pressure, such as a vacuum pump.

Each of the closure members is likewise illustrated as having communication with a source of subatmospheric pressure through a line 36 for withdrawing excess vehiclefrom a plastic composition such as concrete, which is deposited in containing grooves 49 in which the deposited.

concrete 42 will become interlocked. The closure member [5 may be formed from two'sections of plywood or the like arranged at right angles and reinforced by an angle 44. The internal or mold-v ing surface of the closure I6 is bounded by a sealing member 4E of strip rubber or the like which bears upon the adjacent edgeportions of the spaced precast structural members between which the joint is to be produced. The portion of the closure molding surface intermediate this marginal sealing means isfaced with a woven fabric 48 pervious to water or other vehicle to be withdrawn but impervious to the solid particles of the composition bein molded.- The fabric is supported out. of contact with the closure body by. means of woven wire mesh 50 or the like so that the subatmospheric pressure. produced;

4 through a projecting nipple 52, by means of a vacuum pump connected therewith by a conduit 36, will be substantially uniformly distributed over the adjacent surface of the composition 42. Since the concrete or other plastic composition is usually quite plastic when firstdeposited, its static head requires appreciable force for'retention of the closures at the outset, produced in this case by the use of vacuum operated holders. For this purpose the closures I8 and 20, which maybe constructed of a suitable number of layers of plywood areapplied to portions of the structural members adjacent the closure by means of subambient pressures produced through a suitable number of nipples 54 and conduits 34 leading to a vacuum pump. The wall engaging surfaces of these holders carry yieldable sealing me'mbers'56 formed of sponge rubber or the like retained between suitable strips or beads 58. Similar sponge rubber supports 60 are provided intermediate the sealing members, particularly where the spans involved would'other-l wise produce excessive stresses upon theiholder body under the subambient pressures: encoun-' tered. To assure a quick and positive sealv be-i" tween the holders andthe wall surfaces toiwhich they are applied, even where such surfaces are" somewhat rough, thinjrubber sealingflaps 62 are secured to the sealing members 5,6 to; extend therebeyond for engagement with an. appreci able area of the wall, which flaps may assumejthe form of limp resilient and thin material sucli'a'si yellow balloon rubber. Overhangingportions'ofthese holders provide projections 64'whic'h1'er'rgage a, portion of the closure to 'force it into its operative position when the holder iszapplied to the wall and its sponge rubber sealing members and supports yield under the, influence. 'ofthesubatmospheric pressure produced betweenthe" holder and the wall asshownin Fig. 2;

structural members.- In the caseillustrated 'in Fig. 2, the internal holders are somewhat na'rrower and somewhat thicker than thei'ex'ternal holders.

In applying the invention; withltlie structural members Ill and I2 in erected position,-the;in-

ternal and external closures are applied; theseparable holders positioned to bear upon their? and subatmospheric' pressure is then introducedbetween the holders and the structurarmembr'sthrough the conduits and nipple provided for this purpose. This will result in securing closures in. position, whereupon the v plastic mixk is introduced into the form-thus defined and sub atmospheric pressure is applied to the mix through the perforate surfaces of one or'both of the closures. vAs soon as a predetermined portion of the excess vehicle has been with-- drawn from the mix, the composition begins to become self supporting and the static hea'd b comes reduced sufficiently to permit discontinu ancev of. the subatmospheric pressures applied between the holders and the structural members and the .holders themselves can then-be removed. In'due time, the-subatmospheric pressure applied'to the compositionthroughthelo sure or closures can also be discontinued and the closures removed.

In some instances, particularly where the thickness of the column or joint is small, it may be unnecessary to apply subatmospheric pressure both internally and externally of the concrete, which case one of, the closures may serve merely as a barrier to retain the mix in positionjwhile the subatmospheric pressure is applie to the opposite surface alone. In such a case, one of the closures may assume a simpler form.

It will be understood that the running joints or columns may be produced with similarly separable closures and holders, differing in configuration to accommodate the shape which it is desired to impart to the molded material. It is contemplated for some applications of the invention; to construct the closures and holders in a unitary fashion, as disinguished from separably, as has been depicted in Figs. 3 and 4. In these figures, the closure 28 and the holders 3!] are suitably joined together by bolts, screws, or the like, so that the assembly may be applied as aflunit to the spaced structural members between which it is desired toproduce, a molded joint. Inasmuch as the elements composing, this form of the invention are similar to those" described with reference to the preceding figures} they have been similarly identified and:

willreq uire no extended discussion. It will be noted that the intermediatesupports 60 best shown in Fig. 3 can be terminated or extended as desired to best suit the surface to which it is applied. It will be understood that the closures and holders for such running joints might well be separable in the manner described with reference to the corner joint previously described, bearing in mind that where the construction is unitary, the entire assembly must be retained in position until the composition has become sufficiently self supporting to permit its removal.

Thes ibatmospheric pressures applicable to the plastic composition will assume values in the rangesfdisclosed in the Billner Patent No. 2,046,867, dated July '7, 1936, and the subatmospheric pressures applied to the holders will be as great or greater. The eifective area of the holder or holders for a given closure opposed to a cooperating surface will be computed in each application to exceed that necessary to retain the form equipment and plastic composition in position'for the value of subatmospheric pressure to be used.

By the term subatmospheric employed throughout this specification and in the claims to characterize pressures, is intended a pressure condition below that of the surrounding atmosphere, whether that atmosphere be ordinary air at natural atmospheric pressure, some fluid other than air, or some different pressure. For example, if the apparatus were employed in a pressure chamber or under water, the atmospheric pressure would be that of the medium surrounding the operation, and-subatmospheric pressure would be a lower pressure.

This application is a division of application Serial No. 772,324, filed on September 5, 1947, which matured into Patent No. 2,548,935, April 17, 1951.

Whereas but two specific embodiments of the invention have been described with reference to the drawings, many variations will occur to those skilled in the art as they have been recognized already by the present inventor, rendering it important that these examples should not be construed to restrict the invention beyond the scope of the appended claims.

- I claim:

1. A form for casting a moldable plastic composition between spaced structural members comprising a molding surface for contact with said composition, sealing means substantially bounding said surface for engagement with a surface portion of said members, holding means connected with said molding surface comprising av mat having sealing means for engagement with an adjacent surface portion of said members,

' andmeans for applying subatmospheric pressure said composition, sealing means substantially bounding said surface for engagement with a surface portion of said members, holding means connected with said molding surface comprising 7 a mat having sealing means for engagement with an adjacent surface portion of said members,

means for applying subatmospheric pressure intermediate said holding means and said adjacent surface portion, and means for applying subatmospheric pressure through said molding- "surface to said composition.

'..3. A form, for casting a moldable plastic compositionbetween spaced structural members comprising a perforate molding surface for contact with said composition, sealing means substantially bounding said surface for engagement with a surface portion of said members, holding means connected with said molding surface comprising a mat having sealing means for engagement with an adjacent surface portion of said members. means for applying subatmospheric pressure intermediate said holding means and said adjacent surface portion, and means for withdrawing excess vehicle from said composition through said perforate molding surface.

4. A form for casting a moldable plastic composition between spaced structural members comprising an angular molding surface for contact with said composition, sealing means substantially bounding said surface for engagement with a surface portion of said members, holding means connected with said molding surface comprising a plurality of mats having sealing means for engagement with an adjacent surface} portion of said members, and means for applying subatmospheric pressure intermediate said holding means and said adjacent surface portion.

5. A form for casting a moldable plastic composition between spaced structural members comprising a molding surface for contact with said composition, marginal sealing means bounding said surface for engagement with a surface portion of said members, holding means connected with said molding surface comprisin a mat having sealing means for engagement with an adjacent surface portion of said members, and means for applying subatmospheric pressure intermediate said holding means and said adjacent surface portion.

6. A form for casting a moldable plastic composition between spaced structural members comprising a molding surface for contact with said composition, sealing means substantially bound ing said surface for engagement with a surface portion of said members, holding means integral with said molding surface comprising a mat having sealing means for engagement with-'a'nadjacent'surface portion of said members, and means for applying subatmospheric pressureintel-mediate said holding means and said adjacent surface portion. v

7.- A form for casting a moldable plastic composition between spaced structural members c'om prising a molding surface for contact with said composition, sealing means substantially bound-' ing said surface for. engagement with asurfa'c'e" portion" of said 'members, separable holding means'connected with saidmolding surface comprising a mat having sealing means for engage-- ment with an adjacent surface portion ofsaid members, and means for applying subatmospheric pressure intermediate said holding means and said adjacent surface portion.

8. A form for casting a moldable plastic composition between spaced structural members comprising a molding surface for contact with said composition, sealing means substantially bound- I molding surface comprising a mattfo'fr engage ment with an adjacent surface portion of said members, sealing means interposed between said surface, mat and 'members; said sealing means including meanssubstantially bounding said-sur face, and means for applying =subatmos'pherid' pressure intermediate said holding means and said adj acent surface portion.

10; A form for casting a moldable plastic-com position between spaced structural members come prising a molding surface for contact with said composition, holding means connected with saidmolding surface comprising a mat for engagement with an adjacent surfaceportion of said members, sealing means for said surface, mat

and members, said sealing means includingmeans substantially bounding; said surface; means for applying subatmospheric pressure intermediate said holding'means and said adjacent surface portion, and means for applying subat mospheric pressure intermediate said surface;

and composition.

' KARL P. BILLNER.

REFERENCES CITED The following references are of record in they file of this patent:

UNITED STATES PATENTS Number Name Date V 958,419 Mowat May 17', 1910 1,630,801 Parsons May 31, 1927- 2,474,721 Billner June-28,1949 

